Browsing by Author "Cheng, H. H."

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Electrical characteristics of Ni Ohmic contact on n-type GeSn
(2014-06-16)
Li, H.
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Cheng, H. H.
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Lee, L. C.
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Lee, C. P.
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Su, L. H.
We report an investigation of the electrical and material characteristics of Ni on an n-type GeSn film under thermal annealing. The current-voltage traces measured with the transmission line method are linear for a wide range of annealing temperatures. The specific contact resistivity was found to decrease with increasing annealing temperature, followed by an increase as the annealing temperature further increased, with a minimum value at an annealing temperature of 350 degrees C. The material characteristics at the interface layer were measured by energy-dispersive spectrometer, showing that an atomic ratio of (Ni)/(GeSn) = 1:1 yields the lowest specific contact resistivity. (C) 2014 AIP Publishing LLC.
Non-lethal Candida albicans cph1/cph1 efg1/efg1 transcription factor mutant establishing restricted zone of infection in a mouse model of systemic infection
(2006-07-01)
Chen, C. G.
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Yang, Y. L.
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Cheng, H. H.
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Su, C. L.
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Huang, S. F.
The cph1/cph1 efg1/efg1andida albicans mutant cells were non-lethal in a mouse model of systemic infection. We investigated in vivo proliferation and invasion of C albicans cells in infected mice to elucidate the interaction between the host and the pathogen. Homogenates of kidneys from the mice infected with the wild-type and the mutant C albicans cells yielded a mean of 2.1 x 10(7)CFU/g and 2.2 x 10(6) CFU/g, respectively. The kidneys from the mice infected with the wild-type cells showed extensive renal cortical necrosis associated with neutrophilic infiltration. There were also wild-type hyphal cells present in abundance. Hence, tubular necrosis leading to renal failure in the mice may be the cause of death. Although the cph1/cph1 efg1/efg1 mutant cells were not lethal, they were capable of establishing restricted zones of infection and colonization near the renal pelvis instead of simply being cleared by the immune system in mice.
Probing Landau quantization with the presence of insulator-quantum Hall transition in a GaAs two-dimensional electron system
(2008-07-23)
Chen, Kuang Yao
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Chang, Y. H.
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Liang, C-T
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Aoki, N.
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Ochiai, Y.
Magneto-transport measurements are performed on the two-dimensional electron system (2DES) in an AlGaAs/GaAs heterostructure. By increasing the magnetic field perpendicular to the 2DES, magneto-resistivity oscillations due to Landau quantization can be identified just near the direct insulator-quantum Hall (I-QH) transition. However, different mobilities are obtained from the oscillations and transition point. Our study shows that the direct I-QH transition does not always correspond to the onset of strong localization.
Type-I/type-II exciton in strained Si/SiGe multi-QWs
(2008-03-01)
Wang, K. Y.
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Huang, W. P.
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Lin, T. C.
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Lee, C. P.
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Sung, Y. T.
Using magneto-luminescence (ML) measurement, we have observed the formation of magneto-excitons with either type-I or type-II band alignment depending on the strain distribution in the Si/SiGe quantum well structures. This observation is consistent with the analysis of strain-induced band shifting and exciton-transition energy. (c) 2007 Elsevier B.V. All rights reserved.